Magnetic nanoparticles (MNP) have become important tools for clinical cancer imaging. A number of monocrystalline and ultrasmall iron oxide preparations have been developed over the last decade and shown to significantly improve the accuracy of nodal cancer staging, angiogenesis imaging and mapping of tumor host response. More recently, magnetofluorescent nanoparticles have been developed for pre-operative staging and intraoperative tumor localization. Despite these advances, there are no molecularly targeted MNP in clinical development because of the lack of stable and biocompatible MNP preparations. The overall goal of this project is to explore the synthesis of next generation, clinically viable MNP preparations through the use of systematic evaluations of polymer libraries and the use of optimized conjugation chemistries. This project will interact closely with the Langer lab in synthesizing and testing different polymers as coating materials and with the Belcher/Bawendi lab for comprehensive materials analysis. Finally, we will test new preparations in mouse models for prostate cancer detection. This projects will lay the ground work for the next generation magneto/fluorescent nanoparticles that encompass high stability, reproducible chemistry, optimized pharmacokinetics and in vivo targetability.